Over the course of time, and in particular under the action of external conditions such as light or harmful atmospheric substances, hair loses or changes the natural color thereof and the luster or sheen thereof. Hair dyes are widely used for this reason, which are employed either in salons or as at-home use.
What are known as oxidation dyes are used for permanent, intensive colorations having appropriate fastness properties. Such dyes usually comprise oxidation dye precursors, so-called developer components and coupler components, which create the actual dyes among each other under the influence of oxidizing agents or of atmospheric oxygen. The oxidation dyes are characterized by outstanding, long lasting dyeing results. Permanent or semi-permanent coloring agents including what are known as substantive dyes (direct dyes) as the coloring component are typically used for temporary colorations.
In addition to coloring, lightening one's hair color or blonding has always been a very special desire of many consumers since a blond hair color is perceived to be attractive and desirable from a fashion point of view. When substrates are to be lightened or even bleached, the dyes coloring the substrate are typically decolorized oxidatively, using appropriate oxidizing agents, such as hydrogen peroxide.
The problem with dyeing hair, and in particular dyeing hair by way of at-home use, is that natural color nuances are completely covered, whereby multi-tonal colorations are difficult to implement.
So as to impart a more natural appearance to the hair, it is known from the prior art to partially decolorize dyed hair by deliberately applying oxidizing agents. The sections of hair (“strands”) to which the oxidizing agents are applied result in bleaching at least in some proportion, resulting in a multi-tonal hair color. The oxidizing agent is applied by way of a brush, wherein the hair that is not to be treated is optionally protected from decolorization by way of an aluminum foil or what is known as a “highlighter cap.”
While this kind of application solves the problem of dyeing hair as naturally as possible, a time-consuming second decolorizing step is needed, which follows the first coloring step. In particular in the case of at-home use, initially the entire hair would thus have to be colored before the user is able to add highlights. Many female consumers consider this too time-consuming, as well as frustrating, since the essential color-modifying step takes place first and is then merely “corrected” in a second step.